Dermatology: Practical and Conceptual


Image Letter  |  Dermatol Pract Concept 2020;10(4):2020072 1

Dermatology Practical & Conceptual

Case Presentation 

A 34-year old female with an unremarkable medical history 

presented with a 3-month history of scalp pruritus. Physical 

examination revealed small whitish lesions resembling nits, 

abundant on one dreadlock. Trichoscopy showed many whit-

ish, tubular and non-adherent structures on the hair shafts 

(Figure 1). There was no evidence of nits or lice on the rest 

of the scalp.

Teaching Point

Pseudonits, hair casts, or keratin cysts are white objects that 

easily move along the hair. There are 2 types: (1) paraker-

atotic, associated with seborrheic dermatitis, psoriatic or 

excessive traction, and (2) peripilar, the pathogenesis of which 

is not clear but is more frequent in young women. Trichos-

copy findings include whitish cylindrical structures around 

the hair shaft. Nits (main differential) present brown ovoid 

structure with a curved end (vital) or translucent structure 

with a planar end (empty). Pseudonits are frequently misdi-

agnosed as pediculosis capitis; trichoscopy, then, is essential 

for differentiation, avoiding patient anxiety and unnecessary 

treatments.

Pseudonits or Hair Casts
Vania Lukoviek1,2, Josep Malvehy1, Susana Puig1, Sebastian Podlipnik1

1 Department of Dermatology, University of Barcelona, Spain

2 Department of Dermatology, University Hospital of Canarias, Tenerife, Spain

Key words: pseudonits, nits, dermoscopy, polarized light dermoscopy

Citation: Lukoviek V, Malvehy J, Puig S, Podlipnik S. Pseudonits or hair casts. Dermatol Pract Concept. 2020;10(4):e2020072.  
DOI: https://doi.org/10.5826/dpc.1004a72

Accepted: April 16, 2020; Published: October 26, 2020

Copyright: ©2020 Lukoviek et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, 
which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Funding: None.

Competing interests: The authors have no conflicts of interest to disclose.

Authorship: All authors have contributed significantly to this publication.

Corresponding author: Sebastian Podlipnik, MD, PhD, Melanoma Unit, Dermatology Department, Hospital Clinic Barcelona, Villarroel 
170, 08036, Barcelona, Spain. Email: podlipnik@clinic.cat 

Figure 1. Trichoscopy reveals pseudonits.



2 Image Letter  |  Dermatol Pract Concept 2020;10(4):2020072

2.  Lokhande AJ, Sutaria A. Adult onset hair casts: nits which do 

not itch! Int J Trichology. 2017;9(2):70-72. DOI: 10.4103/ijt.

ijt_30_17. PMID: 28839391.

3.  França K, Tadeu Villa R, Rezende Silva I, Almedia Carvalho C, 

Bedin V. Hair casts or pseudonits. Int J Trichology. 2011;3(2):121-

122. DOI:  10.4103/0974-7753.90834. PMID: 22223977.

Acknowledgments 

Thanks to our patients and their families who are the main 
reason for our studies; to Paul Hetherington for helping with 
English editing and correction of the manuscript.

References

1. Lacarrubba F, Verzì AE, Micali G. Trichoscopy in the differential 

diagnosis of pseudonits. Skin Appendage Disord. 2019;5(3):142-

145. DOI: 10.1159/000493741. PMID: 31049334.